Mouryou no Hako seems to be a symbolic anime, like Paranoia Agent and Serial Experiments Lain. For these of anime, you have to take a closer at than most, because most is explained via symbols, like Maromi in Paranoia Agent.

The only thing you can do to uderstand these kind of anime better, is:
1 Watch the whole series (I know most of it isn't subbed yet)
2 Watch it multiple times (it's been a year since I watched Serial Experiments Lain, and I still don't understand it. I'm going to take a closer look at it soon)

So, you can only wait until the whole series is out to understand it. If the idea doesn't appeal to you, just stop watching, it'll only aanoy you in that case.